PLEASE help my poor mum!

holty

Inside a nice VAG
Sep 25, 2008
202
0
In the Hills
Hi folks,
My mum has just bought a second hand Polo TDI pd100.
It has now developed a strange 'farty' noise mostly at low speeds.
I've located it and its coming from a black box with I think 6 wires/small pipes coming off it
in the top left of engine bay if looking with bonnet up.
I've also actually seen the box vibrate after ignition goes off and it leads to a valve/diaphragm which momentarily twitches open.
Here is a pic i've got off the net of the of a similar looking bay.Couldn't find an exact match!
williamsruss

The arrow points to roughly where the valve is and the box is around the vibrating area.
Any help greatly appreciated.
I think she is very gutted as its her first decent car!
I promised i'd ask you lot to help!
 
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warren_cox

Back from the dead
My immediate though was that the black box with pipes coming out may have been an ABS pump, but then I wondered if it is the fuel pump system for the Pumpe Duse system.

Either way I get it checked by an independent as you wouldn't want failures on either.
 

holty

Inside a nice VAG
Sep 25, 2008
202
0
In the Hills
Thanks Warren.
I think she's booked in somewhere tomorrow.Just trying to find out on here what it could be so she doesn't get ripped off!
 

muddyboots

Still hanging around
Oct 16, 2002
5,739
1
The black box distributes vacuum to various components, including the turbo VNT actuator, EGR valve and ASV.

The valve that mometarily switches open when you turn the ignition off is the ASV (Anti Shudder Valve), this closes a flap to temporarily block the air inlet to the engine, to stop the TDI engine shuddering when it comes to a halt.

Are you sure the farty noise is coming from the box itself, or could it be from the pipework leading to it or another nearby component ? IE have you put your ear right next to it ?
Do you hear the noise only at idle, or when driving/accelerating ?

It's a leak of some sort - either a vacuum leak from the box or connected pipes, or maybe a boost leak from an inlet pipe when you accelerate.
 
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Muttley

Catch that diesel!
Mar 17, 2006
4,987
31
North Kent
It's more than that, it's a solenoid box, and contains all the bits that were formerly separate valves like the N249, N18, N75 etc.

Pipes go to turbo actuator, vacuum reservoir, air box (source of atmospheric pressure), intake flap actuator, EGR actuator and to the tandem pump (vacuum source) which feeds the brake servo directly.
 
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